This Core Laboratory results from the close collaboration of the co-investigators and scientists for over 20 years in conducting microbiological, immunological, biochemical, molecular, and histopathological studies of otitis media. This experience and expertise is now combined into one Core facility, which will support 14 base projects, promoting interdisciplinary research with the capacity of enhancing base project objectives. The Core will provide expertise and techniques in microbiology, immunology, biochemistry, molecular biology, and histopathology. It will also provide antibodies, probes, archival samples, and bacteria or bacterial components. Quality assurance, documentation, integration of new methodologies, and new model developments are underlying features of the Core. The team's expertise includes design and integration of new, more sensitive analytical and pathobiological assays, proactive laboratory management, database development, data interpretation, statistical quality, and process control. This Core contributes to study design, data generation and interpretation, quality assurance, and data analysis of all supported research projects submitting study samples to the Core. Data analysis is closely coordinated with the Human Subjects/Biostatistics Core. The key areas are quality assurance, assay standardization, and utilization of the most sensitive methodologies available. To achieve its specific aims, the Core will perform its assays using standardized protocols, and will monitor and immediately correct any assay drift or performance variations within those assays. In addition, the Core will develop innovative technologies to meet the desired aim-enhancements of the project PIs. A member of the Core is proactively involved within each of the supported research projects at all stages of development. This involvement includes advising the investigators on those assay methodologies best suited to accomplishing the investigator's goals with respect to the analytical pathobiology results required for the project.